1. Field of the Invention
This invention relates to side guides for use in rolling steel rods such as square or circular steel rods.
2. Description of the Prior Art
Caliber rolls have been generally used in rolling elongated metal rods such as square, rectangular or circular cross-sectional rods and wires of steel and non-ferrous materials. The term "steel rod" used in this specification and claims is intended to designate such elongated metal rods of all kinds.
Caliber rolls or rolls whose barrels are formed with calibers for rolling steel rods, however, impose great difficulties in machining the calibers and there is a risk of breaking off due to reduced diameters at calibers, so that the rolls are required to have large initial diameters to avoid the breaking off at the calibers. A great number of caliber rolls of various kinds must be prepared for sizes of rods to be rolled, which require changing of the rolls depending on the sizes of rods and centering adjustments between caliber flanges of a pair of rolls and between the caliber flanges and guides to give rise to extra down time which would be further increased for repairing decayed or damaged calibers due to melting or burning by grinding. In rolling the steel rods by the caliber rolls, moreover, reductions of the materials at corners of the calibers are increased particularly so as to cause larger fishtails on the materials which must be removed from the rods resulting in increased waste materials. Furthermore, resistance to reduction of the material in the calibers is comparatively high which would unavoidably increase the power cost.
In stead of the caliber rolls used in rolling steel rods therefore, the use of caliberless or grooveless rolls having simple cylindrical surfaces without calibers has been proposed and experimentally used in for example alternate horizontal and vertical roll arrangements in order to overcome the above disadvantages. However, such an attempt has not succeeded in practical processes.
The term "grooveless roll" or "caliberless roll" used herein means a roll which is not formed with a caliber or calibers in its barrel.
The invention lies in the discovery in experiments on an actual operation scale that the results of rolling are greatly affected by the fact that there are no holding means for rolled materials in gaps between caliberless rolls. In contrast herewith, caliber flanges of the caliber rolls serve to prevent the steel rods from twisting and overturning or deforming into incorrect (parallelogram) cross-sections, although guides arranged on the entry and exit sides only serve to guide the steel rods into the calibers at locations remote from the calibers. In view of the discovery, the inventors conceived side guides for rolling steel rods capable of retaining steel rods to be rolled through gaps between the caliberless rolls.